Spongiacysteine, a Novel Cysteine Derivative from Marine Sponge Spongia sp.

A novel cysteine derivative, spongiacysteine (1), was isolated from marine sponge Spongia sp. The gross structure was elucidated by detailed spectroscopic analysis, and the absolute stereostructure was established by its total synthesis. This compound showed moderate antimicrobial activity against rice blast fungus Pyricularia oryzae.